Method of and material for sealing containers



METHOD OF ANDMATERIAL FOR SEALING CONTAINERS Filed Oct. 51, 1928 vHg/ 0 y v/0 fjBnTHEi. JAY :BABBVITTQOTRIYEBSIDE rLLINois, AssieNoR'To WESTERN ELECTRIC. y

" Y 1 ooMrANY, INcoRronATnD, or yNew Yonx, N. Y., A eoRroRATroN or NEW YORK ,i This inventionfrelates tothe k.heat treating; ofi articles Yand more particularly to the'an o "NETHONF AND MATERIAAL For;*snALINey CONTAINERS n Application led October 31,1928. SerialNo. 316,146.`

l"l'nealing*of'metal'articles f y .Y

v 'iIn the heat treatingof iron articles it'has been customaryto store the articles in aconyfftainer''having ajclosely fitting.y lid. Inorder Uto secure. the desired .atmospheric `conditions withinthel container, it has beenithe vpractice .'fin-some instances to sealy the yjoints Nof thelid .-and. containerwith a packing .material such .f as cupola loam. J'lhe loambeing moist and nioreor-less viscouspermitsthe escapetof :gases occasioned by they expansion of the air p within the box duetoincreased temperature.Y In the f concluding part* 'of the process,rthe Y' z'loamzbeconie's quite hard kdue to the rheat, to

. which it yis exposed vand thus? assists, upon VVVfrom thefurnacev Y l ,Y f f IThe objectf-ofV the present invention is to'`l provide animproved method of andinaterial fcooling, yin preventing the entrance of. air Vto the interior -of the,y b ox'due'fto ,atmospheric pressure after the containerfis.withdrawn rfor securing 'desired .atmospheric conditions `Within azcontainerg* y@ .f "f: According to the'featuresof the invention v y a mixture`,preferablylin powder. fom of app-r, Y pro'ximately equal parts by. weight of ka pene.'

v trating Vmaterial V'such Vas lead borate, and a crust forming material such .asglass, `isfden epositeduponthe loam covering thejoints of f j the container to permit the escape of thegases yrduringthe annealing operation and to pren .vent the f entrance of lair. during they subsef v 35'- -@It is believed theinvention will` be more clearly understood vby reference toj'the i f companying drawings, inawhichy `quent cooling of the parts. v

Y, fl-represents apvertical section of` a m.,

loaded annealing v t container prepared for .heating,and f' n n 'Fig. 2k represents a fragmentaryvertica-l. section showing'fthefj condition of fthe seal ``V`upon,completionof,the process.' l' j u.In-,1, the drawings; fan annealing container ifgenerallykr denoted the VI'iumeral 10 comg prises a i vertical wall 1-1, the uppery portion'y K,

of which consists of lan,upwardly projectingr lip 12 and. an'inner portionl.y Suitably 'arrg ranged/within ,they container. is -a'desired acl "thereto s v e y It is welllmown that types of glass in f for general-purposes being known as easily f fusibley typesland highly refractory.types.,

the'v inner portions 13 is atray 15 upon which is placed asuitable quantity ofmaterial 16 capable of absorbing a large portion 'of' the; joxygen remaining inthe container afterthe oxygen content is material-1y reduced' by heat expansion, yand a' suitable f quantity of` an easily oxidizable metal 17 capable of absorb- .ving the yoxygen content of the container "ati the higher temperatures attained in the proc-y ess, preferablyas described in the applica-y 'tion of R. V. 'Wilsorh for a method of heat treating -inetal parts, Serial No. 316,149, filed October 31,1928. It should beunderstood,i i

however, that the present invention is independent ofthe use of oxidizable metalk or/of otherfineans for; reducingy the quantity of yoxyg'en'inthe annealing container.;y A groove n g n' 'i 18 comprising the area between the inner portions 1Sv andthe upwardly projecting lip 12',

is packed yfull, with. a packing material 19,

the loam around the circumference of the' lid. After fusing, the sealing mixture assumes by the numeral 23.

they method commercial use fall into two broad classes,

`For the purpose of clarity the sealing maf. 'terialfconstituting the features of applicants *.inventionwill be described first, the steps of` `being described subsequently f preferably composed of moistened cupola f I ,gloam. A lid 20 designed toy cover the con? .}tainer, tray and contents and having a del .f pending flange 21yis shown, the depending Y V,flange extending through the loam to the bottom ofthe groove 18. A' suitable quantity of sealing mixture k22 is shown sprinkledon p the conditionshown in Fig. 2, and is denoted Experience has shown that'in order'to pro` i vcure a' glass'whi'ch would be easily fusible,- boron-insome form must bey added to the' mixture. It is also known that the' melting pointof a glass inthe highly yrefractory clients.

group may belowered by the addition yof a. suitablequantity of boron totheother ingre-y l n i,

In compounding the Vsealing mixture, it has been found advantageous to use certain pre-y determined proportions of the various materials. hereinafter specified, but it should. be understood'that those Yproportions are not fixed and that satisfactory results maybe securedeven thoughthe proportions of the materials specified be considerably.' varied. Approximately 34 pounds of powdered boric vacid is thoroughly mixed with 166 pounds of dry red lead in' a ball mill. A frit furnace heated to atempcrature of 19009F. is placed over a pan of watery to insure a suitable receptacle for the molten fritas itflo-ws from the furnace. A portion of the mixed vbatch is f then'placed in the heated furnace and allowed to'run out vinto the water as it melts. The frit (lead borate) 'is removed from the water land thoroughly dried at a temperature ranging from 2500 to 3000V-F. Y Approximately f 150 pounds 4of, the dried Vlead borate is put l through aV ball lmill and. ground for about twohours and screened lthrough a 6d! mesh screen. Approximately 150 4pounds ofthe Yother boron compounds appropriate for mixing with' the red'lead may be used, such as l `sodium tetra borate, colemanite, etc. Pracically equivalent results maybe obtained by fusing compounds otherthan red lead, such asl the various-lead oxides, barium, sodium and barium, etc., the 'importantconsideration A being .thata' glass befproduced which will be @capable ofV fusing`V ata considerably Vlower temperature than vthose glasses inthe highly .refractory group. Likewise, although ground scrap glass seem-sto be! preferable, other highly refractory substance such'as porcelain,

flint, silica, felspar, etc., may be used.y

VAlthough the above method of `preparing the sealing mixture represents an economical and efficient means of producing the sealing fmaterial in the desired form, it should, nevertheless, be understood that it represents' only one. of a number of well known methodsof *accomplishing the desired results and the present invention is not to belimited byany of the steps indicated above.

. In utilizing the material specified, a con-` ventionalannealing container is loaded with a. desiredquantity of articles to' be annealed,

andthe groove 18, which extends completely around the container, is packed full withV a cupola loam. Thetray is Vplaced init/he v container in such manner that it rests upon the innerportions 13 of the sidewalls, andffUp'on the gradual lowering ofthe tempera- 130 -mg mixture such asmay be employed in Leidee desired quantity of 'oxygerrabsorbing maA terial is placed thereon. Y The lid is placed over the container and pressed down, its depending flange 2l being forced downwardly into the groove. The excess loam which is thereby forced .from lthe grooveis removed andthe upper surface'of the loam 'is troweled with a suitabletool (not shown) in this way forining'a sealwhich, at ordinary temperatures, would" bej air-tight, ijf'Ajldesiredfquantity of the sealing mixturedescribed above is sprinkled ontle topjsurface of theloam around theV circumfereiicebf the container. rlhe container being now fully prepared, is placed in a furnace and subjected to the range of temperature customarily employed in an fannealing process. 1

t is obvious that asthetemperature of the *container and contents is .'raised,the'airv withinthe container expands and is forced out through the loam which is Ystill moistV and somewhat viscous. As the temperatureis steadily .'increased, Vthe ygases withinthc .cen-

tainerexpand andare continuallyforced out through the mud seal, which in a very short time loses its moisture content." Since the customary range of temperatures withinlthe first portion of thel annealing process, from 50 to 2000o F. 'isprogressively scaled from low-to vhigh temperaturespit will beseen that iinders the escape wof gases Vfrom the4 box, due to thefact that duringthe periodof rise in temperature, when the gases are Vbeing forcedfouhthe seal is'either in a powdered or liquid state. As the temperature is increased to a point commensurate'fwith the fusing point4 of the leadjborate, that portion of the mixture fuses and the Vground glass comprising theremainder of ,the mixture imme- "diately goesinto solution with the fused lead borate. The.v tendency ofl the fused lead fborateto flow'causes a distribution-lof' the solution over :the surface of the loamforming anjintimate contact with the upper edge of theiupwardly projecting lipf12 andthe edge ofthe lid 18. The tendencyof the 'fused lead vberate to seepdownwardly through the loam is counteracte'd at this stage by its being ink solution with the Ystill unfused ground glass.v As 'thev temperature is increased the viscosity of the'sealing mixture is decreased' proportionately, thus causing an 'even'distribution of the material over the surface of the loam. At the higher temperatures inthe range ofthe annealing process, the ground glass Y fuses and, having been previously in Vsolution withv the viusedlead borate, forms a conglomerate frnolten mass which, as the temperature is increased still *higher-1, becomes less viscousthan formerly and seeps downward throughv the loam toa ii'certain extent, until the' freelyV flowing l"surplus has been'ab'sorbed bythe-packedliloam.

the 'sealing mixture employed in no 'way `ture'of the container, the ...conglomerate seal r`formed* on the surface of theloam cools andy hardens and since, in* its :less viscousvstate,

I it vhas become evenlyk distributed,l overand y through the upper surface ofthe loam, it

forms a perfect lseal upon hardeningfwhich is y f vcapable of resistingy the tendency of yair to flow into thefcontainerduejtoatmospheric pressure during the; cooling step off'the m process. l

' *Upon completion of the 'annealing theseal is broken in order to permit the removal'of f theliol. Owing to the fact that it isy neces-y ;'sary to use a comparatively smallamount ofL mixture over a` given: area,' the breaking ofy Y the conglomerate seal'rmay bek accomplishedk with only a trifle greater effort than was formerly required to. break the loam seal,

l both operations being easily accomplished."

manually byl meansrof a trovvel orsimilar t f tool. v u f The" loamunderthe top crust provides a relativelysoft support'for the-hardcrust'and f it is'vtherefore easilybroken Whereasif the {,5 mixture Wasused throughout instead ofjust move it.

Y on' top, it Would be extremely dilicult to' ree What is-claimed is: i y' n l.l vAmethod of sealing heat treating "coni" l,tainers v'vhich consists vin applying a packing ymaterial to theapertures to -be sealed, covering the packing material l.with azmixture of leaol rborate and a hi'ghlyrefractory glass, Y and fusing the mixture. E v y 21A method of sealingheattreating con tainers,v Which consists in applying a packing material tothe apertures to be sealed, covering the packing material With amixture kof lead borate and arhighly,v refractory glass o Whichmixture upon fusing of the lead borate y Will yform a viscous mixture supportedibyy Y the; packing material, and fusingthe lead t borate to form a solution supported yby the 'packingmaterialf L t L a5 '8. A method of sealing heat treating containers, which consists in applying a packingr Ymaterial totheapertures'to bev sealed, cover' f ing the packing material withal mixtureof f refractory glass `anda flux therefor, Aand A 5g fusing the mixture toform valiquid supported by the packing material.

l 4. yA method of; sealingtta heat Vtreating 'container,' which ycomprises yapplying cupola loamV to' the. apertures tov 'be sealed, covering` the loam with a mixtureof refractory glass.

- and lead borate,l and heating the Vcontainer ,A

to fuse themixture. A

In Witness Whereol hereunto subscribe y name this 19th vdayk of October,y A. D.

604192-837 f r*BETHELJAY BABBITT. 

